1.8. About Copyrights and Software Licenses

We're sure that you've read some of the licenses that come with most
commercial software — they usually say that you can only use one
copy of the software on a single computer. This system's license
isn't like that at all. We encourage you to put a copy of Debian GNU/Linux on every
computer in your school or place of business. Lend your installation
media to your friends and help them install it on their computers!
You can even make thousands of copies and sell
them — albeit with a few restrictions. Your freedom to install
and use the system comes directly from Debian being based on
free software.

Calling software free doesn't mean that the software isn't
copyrighted, and it doesn't mean that CDs containing that software
must be distributed at no charge. Free software, in part, means that
the licenses of individual programs do not require you to pay for the
privilege of distributing or using those programs. Free software also
means that not only may anyone extend, adapt, and modify the software,
but that they may distribute the results of their work as
well.

Note

The Debian project, as a pragmatic concession to its users,
does make some packages available that do not meet our criteria for
being free. These packages are not part of the official distribution,
however, and are only available from the
contrib or non-free
areas of Debian mirrors or on third-party CD-ROMs; see the
Debian FAQ, under
“The Debian FTP archives”, for more information about the
layout and contents of the archives.

Many of the programs in the system are licensed under the
GNUGeneral Public License,
often simply referred to as “the GPL”. The GPL requires you to make
the source code of the programs available
whenever you distribute a binary copy of the program; that provision
of the license ensures that any user will be able to modify the
software. Because of this provision, the source code[1] for all such programs is available in the Debian system.

There are several other forms of copyright statements and software
licenses used on the programs in Debian. You can find the copyrights
and licenses for every package installed on your system by looking in
the file
/usr/share/doc/package-name/copyright
once you've installed a package on your system.

For more information about licenses and how Debian determines whether
software is free enough to be included in the main distribution, see the
Debian Free Software Guidelines.

The most important legal notice is that this software comes with
no warranties. The programmers who have created this
software have done so for the benefit of the community. No guarantee
is made as to the suitability of the software for any given purpose.
However, since the software is free, you are empowered to modify that
software to suit your needs — and to enjoy the benefits of the
changes made by others who have extended the software in this way.

[1]
For information on how to locate, unpack, and build
binaries from Debian source packages, see the
Debian FAQ,
under “Basics of the Debian Package Management System”.